Yup everytime I hit a bump in the road in my car, I cringe thinking that I may have shaken the baby out of place...or when I sleep on my stomach, etc.
The thing that I've come to realize is that as small as this little creature is inside of me, it's protected and safe inside there, and there's no way I can avoid every bump in the road or sleep on my back at all times, so I'm trying not to stress about it.